Lance Armstrong arrives at a training session during a rest day of the 2010 Tour de France.
Nathalie Magniez/Getty Images

Tony Pierce with AP|August 24, 2012

The U.S. Anti-Doping Agency stripped Lance Armstrong's seven Tour de France titles Friday, erasing one of the most incredible achievements in sports after deciding he had used performance-enhancing drugs to do it.

Armstrong, who retired a year ago, was also hit with a lifetime ban from cycling. An athlete who became a hero to thousands for overcoming cancer and for his foundation's fight against the disease is now officially a drug cheat in the eyes of his nation's doping agency.

In a news release, USADA said Armstrong's decision not to take the charges against him to arbitration triggers the lifetime ineligibility and forfeiture of all results from Aug. 1, 1998, through the present, which would include the Tour de France titles he won from 1999 through 2005.

Armstrong has strongly denied doping and contends USADA was on a "witch hunt" without any physical evidence against him.

Even though he says he is innocent, cycling champ Lance Armstrong says he will no longer fight charges from the U.S. Anti-Doping Agency that he used performance-enhancing drugs.

"There comes a point in every man's life when he has to say, 'Enough is enough,'" Armstrong wrote on his website this evening. "For me, that time is now. I have been dealing with claims that I cheated and had an unfair advantage in winning my seven Tours since 1999. Over the past three years, I have been subjected to a two-year federal criminal investigation followed by Travis Tygart's unconstitutional witch hunt. The toll this has taken on my family, and my work for our foundation and on me leads me to where I am today – finished with this nonsense.

The USADA claims the 40-year-old Texan, who retired from the sport in 2011, used banned substances starting in 1996.

Thursday the USADA decided it will strip Lance Armstrong of his seven Tour de France titles, and banned him from cycling for life, a move they will officially announce Friday.

By deciding not to fight, Armstrong will also be stripped of the bronze medal he earned at the 2000 Olympics and many other prizes and earnings he won since August 1998.

How do you ban an athlete who has retired? Part of the punishment means that Armstrong will even be forbidden from from coaching or participating in any capacity with any sport that follows the World Anti-Doping Code.

The cyclist claims the process has been unfair.

"If I thought for one moment that by participating in USADA’s process, I could confront these allegations in a fair setting and – once and for all – put these charges to rest, I would jump at the chance," Armstrong wrote. "But I refuse to participate in a process that is so one-sided and unfair. Regardless of what [USADA's chief executive] Travis Tygart says, there is zero physical evidence to support his outlandish and heinous claims. The only physical evidence here is the hundreds of controls I have passed with flying colors. I made myself available around the clock and around the world. In-competition. Out of competition. Blood. Urine. Whatever they asked for I provided. What is the point of all this testing if, in the end, USADA will not stand by it?"

USADA's top boss noted the heft of the day. "It is a sad day for all of us who love sport and athletes," Tygart said. "It's a heartbreaking example of win at all costs overtaking the fair and safe option. There's no success in cheating to win."

"The bottom line is I played by the rules that were put in place by the UCI, WADA and USADA when I raced. The idea that athletes can be convicted today without positive A and B samples, under the same rules and procedures that apply to athletes with positive tests, perverts the system and creates a process where any begrudged ex-teammate can open a USADA case out of spite or for personal gain or a cheating cyclist can cut a sweetheart deal for themselves. It’s an unfair approach, applied selectively, in opposition to all the rules. It’s just not right," Armstrong wrote.

Correction: The USADA had not stripped Armstrong's Tour de France titles as of the time of the original article, but have now.